WBJEE · Maths · Matrices
If \(\mathrm{A}=\left[\begin{array}{rr}1 & 2 \\ -4 & -1\end{array}\right]\) then \(\mathrm{A}^{-1}\) is
- A \(\frac{1}{7}\left[\begin{array}{rr}-1 & -2 \\ 4 & 1\end{array}\right]\)
- B \(\frac{1}{7}\left[\begin{array}{rr}1 & 2 \\ -4 & -1\end{array}\right]\)
- C \(\frac{1}{7}\left[\begin{array}{rr}-1 & -2 \\ 4 & -1\end{array}\right]\)
- D Does not exist
Answer & Solution
Correct Answer
(A) \(\frac{1}{7}\left[\begin{array}{rr}-1 & -2 \\ 4 & 1\end{array}\right]\)
Step-by-step Solution
Detailed explanation
Hints: \(|\mathrm{A}|=-1+8=7\)…
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